点击按钮，form表单提交了两个下拉框的value值后，怎么让下拉框选中刚才提交的值而不是默认的值

求教
<form action="" method="post"  id="FontTrans">
<select   name="ifont" id="ifont" optionString=(String)session.getAttribute("iifont")>
  <option value="">请选择要输入字体</option>
  <option value="Myanmar3" id="Myanmar3" >Myanmar3</option>
  <option value="Wininnwa" id="Wininnwa" >Wininnwa</option>
  <option value="Zawgyi-one" id="Zawgyi-one" >Zawgyi-one</option>
                              </select>                              
</div><input name="bt1" type="button" id="bt1" value="转换"  type="submit" onclick="FontTrans.action='FontTrans.do';FontTrans.submit();"/>
<input name="bt2" type="button" id="bt2" value="字符编码输出" onclick="FontTrans.action='TransFontCode.do';FontTrans.submit();"/><select name="ofont" id="ofont" optionString=(String)session.getAttribute("oofont")>
 <option value="">请选择要输出字体</option>
 <option value="Myanmar3" id="Myanmar3" >Myanmar3</option>
             <option value="Wininnwa" id="Wininnwa" >Wininnwa</option>
 <option value="Zawgyi-one" id="Zawgyi-one" >Zawgyi-one</option>
</select>
</div>
</form>